Flexible printed cards are finding numerous practical applications ever since it became possible to form multiple parallel conductive pads on one surface or both surfaces of thin flexible insulating cards, for example, by etching.
Compared to individual conductors, flexible printed cards have substantial advantages in connecting components of complicated configurations or units moving relative to each other during operation due to such features as their flexibility, ability to pack a large number of conductive pads on a small area and their thinness.
FPC connectors are used to connect FPCs to conducting pads of circuit boards. FPCs and FPC connectors are finding wide use in consumer electronics and office equipment. In consumer electronics, FPCs are used to apply control signals to such devices as liquid-crystal, plasma and electroluminecence (EL) displays which require an extraordinary large number of conductors. They are also used in high-performance electronic equipment, such as microprocessors, to connect transistor components for the transmission of large volumes of data and control signals. FPCs used for these purposes feature a high density of conductors (up to 0.3 mm pitch) and they are commercially available.
Description of design of conventional FPC connectors can be found, for example, in Japanese Utility Model Disclosure No. 3-22869. In this conventional FPC connector, electrical contacts having contact sections in the form of a tuning fork are arranged along a housing opening. A connecting end of an FPC is inserted in the tuning-fork contact sections along with an insulating slider. An electrical connection is made by conductive pads at the FPC connecting end being engaged by contact points of the electrical contacts.
The optimum density for such conventional FPC connectors is of the order of 1 mm pitch between conductive pads, and they can be used with FPCs whose pitch is below 0.5 mm only with considerable difficulties.
In addition, attempts to reduce dimensions of the FPC connector itself result in the compromising of contact springability, thus reducing the reliability of electrical connection.